Continuous and discontinuous drawing: high temporal variability exists only in discontinuous circling in young children

The authors studied whether the drawing variability in young children is best explicable by (a) demands on the explicit timing system, (b) an underdeveloped ability to control limb dynamics, or (c) both. The explicit timing demands were lower in continuous drawing in comparison with the discontinuous task. The authors manipulated limb dynamics by changing the number of joints involved, with line drawing requiring fewer joints than circle drawing. Results showed that young children had high temporal variability in discontinuous circling but not in other conditions. The authors argue that both explicit timing and dynamic complexity of limb control may be determinants of temporal consistency and may thus play an important role in the development of drawing and writing skills in children.     

Aggravation of DSS-induced colitis after chronic subordinate colony (CSC) housing is partially mediated by adrenal mechanisms

Chronic subordinate colony housing (CSC) is a relevant chronic psycho-social stressor for male mice. Here, we investigated effects of CSC on the severity of dextran sulphate sodium (DSS)-induced colitis and the involvement of adrenal mechanisms. After 19 days of CSC, male C57BL/6 mice were treated with 1% DSS (8 days). After 8 days, inflammatory shortening of the colon and the histological inflammation score were increased in CSC mice. Additionally, the increased secretion of pro-inflammatory cytokines by mesenteric lymph node cells found on day 2 and 4 of DSS treatment was down-regulated in CSC mice on day 8 of DSS treatment, paralleled by an increase in plasma corticosterone. In contrast, in unstressed controls, elevation of cytokine secretion was delayed and only found on day 8 of DSS treatment, associated with a prompt rise in plasma corticosterone. To reveal adrenal mechanisms in CSC-induced effects on colitis, mice were adrenalectomized, exposed to CSC and treated with DSS (8 days). In adrenalectomized CSC mice, the severity of DSS-induced colitis was reduced, as body weight loss, shortening of colon, histological damage score, and cytokine secretion from mesenteric lymph node cells were diminished compared with sham-operated CSC mice. In conclusion, exposure to chronic psycho-social stress increases the severity of acute DSS colitis, an effect which is, at least partly, mediated by adrenal mechanisms.     

Action selection and action awareness

Human actions are often classified as either internally generated, or externally specified in response to environmental cues. These two modes of action selection have distinct neural bases, but few studies investigated how the mode of action selection affects the subjective experience of action. We measured the experience of action using the subjective compression of the interval between actions and their effects, known as ‘temporal binding’. Participants performed either a left or a right key press, either in response to a specific cue, or as they freely chose. Moreover, the time of each keypress could either be explicitly cued to occur in one of two designated time intervals, or participants freely chose in which interval to act. Each action was followed by a specific tone. Participants judged the time of their actions or the time of the tone. Temporal binding was found for both internally generated and for stimulus-based actions. However, the amount of binding depended on whether or not both the choice and the timing of action were selected in the same way. Stronger binding was observed when both action choice and action timing were internally generated or externally specified, compared to conditions where the two parameters were selected by different routes. Our result suggests that temporal action–effect binding depends on how actions are selected. Binding is strongest when actions result from a single mode of selection.

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Perceptual identification across the life span: a dissociation of early gains and late losses

The age-correlated gains and losses in visual identification under backward pattern masking were studied in a representative sample of 226 individuals ranging from 6 to 88 years of age. Participants identified masked symbols at leisure under high and low stimulus quality and at varying Stimulus Onset Asynchronies. Performance increased from childhood to early adulthood and then decreased, describing the common inverted U-shaped function. However, measures of general processing speed accounted for the gains in childhood and adolescence but not for losses in older age. This asymmetry between child development and aging is inconsistent with general-factor lifespan theories of cognitive development and suggests that specific mechanisms underlying visual identification during child development and aging are different.     

Intention and attention in ideomotor learning

Human actions may be carried out in response to exogenous stimuli (stimulus based) or they may be selected endogenously on the basis of the agent's intentions (intention based). We studied the functional differences between these two types of action during action-effect (ideomotor) learning. Participants underwent an acquisition phase, in which each key-press (left/right) triggered a specific tone (low pitch/high pitch) either in a stimulus-based or in an intention-based action mode. Consistent with previous findings, we demonstrate that auditory action effects gain the ability to prime their associated responses in a later test phase only if the actions were selected endogenously during acquisition phase. Furthermore, we show that this difference in ideomotor learning is not due to different attentional demands for stimulus-based and intention-based actions. Our results suggest that ideomotor learning depends on whether or not the action is selected in the intention-based action mode, whereas the amount of attention devoted to the action-effect is less important.     

Item performance in visual word recognition

Standard factorial designs in psycholinguistics have been complemented recently by large-scale databases providing empirical constraints at the level of item performance. At the same time, the development of precise computational architectures has led modelers to compare item-level performance with item-level predictions. It has been suggested, however, that item performance includes a large amount of undesirable error variance that should be quantified to determine the amount of reproducible variance that models should account for. In the present study, we provide a simple and tractable statistical analysis of this issue. We also report practical solutions for estimating the amount of reproducible variance for any database that conforms to the additive decomposition of the variance. A new empirical database consisting of the word identification times of 140 participants on 120 words is then used to test these practical solutions. Finally, we show that increases in the amount of reproducible variance are accompanied by the detection of new sources of variance.     

Individual differences in components of reaction time distributions and their relations to working memory and intelligence

The authors bring together approaches from cognitive and individual differences psychology to model characteristics of reaction time distributions beyond measures of central tendency. Ex-Gaussian distributions and a diffusion model approach are used to describe individuals' reaction time data. The authors identified common latent factors for each of the 3 ex-Gaussian parameters and for 3 parameters central to the diffusion model using structural equation modeling for a battery of choice reaction tasks. These factors had differential relations to criterion constructs. Parameters reflecting the tail of the distribution (i.e., tau in the ex-Gaussian and drift rate in the diffusion model) were the strongest unique predictors of working memory, reasoning, and psychometric speed. Theories of controlled attention and binding are discussed as potential theoretical explanations.     

Libido und psychische Energie

The authors investigate different definitions of “psychic energy” and “libido” as well as their critique. With regard to “psychic energy” it is shown that the critique relates in particular to the perspective of Brenner and others and not to Freud's definition. They argue that Freud uses the term “psychic energy” as a synonym for “libido” and not “libido” as a synonym for “psychic energy”. It is assumed that until 1914, Freud related “libido” to manifestations of bodily sexual tensions and afterwards to manifestations of sexual energy in the psychic field. The authors reject this change for epistemological reasons as well as Freud's attempt to use dynamic, economic considerations as an explanatory device. Freud's energy concept is inconsistent with the definition of energy in natural sciences, and, whereas the meta-psychological topographical, dynamic and structural viewpoints have a solid foundation in the representational world to which the psychoanalytic process affords unique access, this is not true of the economic viewpoint. It is claimed that bodily tensions exist in the representational world only in the form of affects, so that the economic viewpoint should, in the authors' opinion, be abandoned in favour of an affective one. In the context of the endeavour to obtain pleasure and avoid unpleasure as adduced by Freud, this viewpoint concentrates on the relationships between affects and the different elements of the representational world, thereby serving as the topoi of meta-psychological investigation dimensions.     

The neural regions sustaining episodic encoding and recognition of objects

In this functional MRI experiment, encoding of objects was associated with activation in left ventrolateral prefrontal/insular and right dorsolateral prefrontal and fusiform regions as well as in the left putamen. By contrast, correct recognition of previously learned objects (R judgments) produced activation in left superior frontal, bilateral inferior frontal, and right cerebellar regions, whereas correct rejection of distractor objects (N judgments) was associated with activation in bilateral prefrontal and anterior cingulate cortices, in right parietal and cerebellar regions, in the left putamen, and in the right caudate nucleus. The R minus N comparison showed activation in the left lateral prefrontal cortex and in bilateral cingulate cortices and precunei, while the N minus R comparison did not reveal any positive signal change. These results support the view that similar regions of the frontal lobe are involved in episodic encoding and retrieval processes, and that the successful episodic retrieval of newly learned objects is mainly based on a frontoparietal network.